Carrier for a solar energy reflector element

ABSTRACT

A reflector element carrier structure is disclosed for use in a solar energy reflector system. The structure comprises a reflector element ( 11 ), a corrugated platform ( 12 ) which carries the reflector element and a skeletal frame structure ( 13 ) which supports the platform. The frame structure comprises hoop-like end members ( 14 ) that are supported by rollers ( 18 ) and the rollers accommodate turning of the carrier structure about an axis of rotation that lies substantially coincident with a longitudinal axis of the reflector element ( 11 ). The combination of the corrugated platform ( 12 ), the frame structure ( 13 ) and the hoop-like end members ( 14 ) of the frame structure provide the carrier structure with a torsional stability that permits the application of turning drive from one end of the structure.

FIELD OF THE INVENTION

This invention relates to a carrier for a reflector element, for use ina solar energy reflector system of a type that is employed forreflecting incident radiation to a solar energy collector system.

BACKGROUND OF THE INVENTION

Various solar energy reflector-collector systems have been developed foruse in harnessing solar radiation that falls incident over areas thatmight range in size from 5×10¹ m² to 25×10⁶ m². In this contextreference is made to collector systems that have been disclosed inAustralian Patents 694335 and 724486 dated 28 Mar. 1996 and 19 Dec. 1997respectively.

The most relevant of the earlier known reflector-collector systems,including those disclosed in the referenced patents, employ a field ofreflectors which are driven to track movement of the sun (relative tothe earth) and which are orientated to reflect incident radiation todistant, elevated collector systems. The individual reflectors are forthis purpose mounted to pivotal supports, but little attention has inthe past been given to the fabrication of economically attractive suchsupports or, in the case of relatively large scale reflectors, to theconstruction of pivotal supports that function to provide torsionalstiffness at a level to resist deflection of the supports and supportedreflector elements.

SUMMARY OF THE INVENTION

The present invention seeks to minimise the above inadequacies byproviding a carrier structure for a reflector element, for use in asolar energy reflector system, and which comprises a platform which isarranged to carry the reflector element and which is formed withstiffening elements, a frame structure supporting the platform, andmounting means supporting the frame structure in a manner thataccommodates turning of the carrier structure about an axis of rotationthat lies substantially coincident with a longitudinal axis of thereflector element when mounted to the platform.

OPTIONAL FEATURES OF THE INVENTION

The carrier structure may, in one embodiment of the invention, becarried by the mounting means in a manner which accommodatesunidirectional rotation of the carrier structure about the axis ofrotation that is substantially coincident with the longitudinal axis ofthe reflector element. By “substantially coincident” is meant that theaxis of rotation is located coincident with or adjacent to thelongitudinal axis of the reflector element.

A drive system incorporating an electric motor may, in accordance withone embodiment of the invention, be provided for impartingunidirectional turning drive to the carrier structure. By providing sucha system, in which unidirectional drive is imparted to the carrierstructure, the traditional requirement for a reversible motor or apivoting mechanism, with attendant backlash and other problems, isavoided. Also, by employing such a drive system, the carrier structuremay be parked in a selected angular position with the reflector elementorientated downwardly, to shield it from adverse ambient conditions,during the process of turning (ie, rotating) the carrier structurethrough 360 degrees during each 24-hour period. Furthermore, the carrierstructure may at any time within each 24-hour period be rotatedtemporarily to a selected angular position with the reflector elementorientated in a direction away from potentially damaging climaticconditions.

The platform for the reflector element may, in one embodiment of theinvention, comprise a fluted or corrugated metal panel, with the flutesor corrugations forming the stiffening elements of the platform. In suchcase, the reflector element will be supported upon the crests of theflutes or corrugations. Furthermore, although the flutes or corrugationsmay extend in a direction that intersects the longitudinal axis of thereflector element, the flutes or corrugations desirably are orientatedto extend in a direction parallel to the longitudinal axis of thereflector element.

Also, although the platform may be formed with a flat surface or suchthat the crests of the flutes or corrugations are located in a flatplane, the platform desirably is curved concavely in a directionorthogonal to the longitudinal axis of the reflector element.

The frame structure of the carrier structure may comprise a skeletalframe structure having hoop-like end members that extend about the axisof rotation of the carrier structure and between which the platformextends. In this optional embodiment of the invention, the end memberswill be supported for turning upon the above mentioned mounting meansfor the carrier structure.

The mounting means for supporting the carrier structure or, in theoptional embodiment of the invention, for each of the hoop-like endmembers, may comprise spaced-apart supporting rollers. Such rollersdesirably are sized and otherwise arranged to track within a channelregion of the associated end member.

The drive system for imparting unidirectional drive to the carrierstructure may, in accordance with one embodiment of the invention, becoupled to at least one of the hoop-like end members and it desirablyincorporates a link chain that extends around and is fixed to one of theend members to form, in effect, a gear wheel. In the latter case asprocket will be provided to engage with the link chain and to impartdrive to the end member from the electric motor. With such a drivearrangement, a relatively inexpensive electric motor may be employedand, with appropriately sized end members of the carrier structure, ahigh reduction in drive velocity and a commensurate increase in torquetransmission is obtained.

The reflector element may comprise a single panel-shaped glass mirror ora reflective metal panel, but it desirably comprises a plurality ofsquare or rectangular glass mirrors that are mounted in edge abuttingrelationship upon the supporting platform. In this case the rear,silvered faces of the mirrors may be protected against adverse ambientconditions by sealing surrounding gaps and spaces with a silicone orother suitable sealant. When, as mentioned above, the platform for thereflector element is curved concavely, the reflector element will besecured to the platform in a manner such that the concavity will betransferred to the reflecting surface of the reflector element.

The carrier structure of the invention may be embodied in variousarrangements, one of which is now described, by way of example, withreference to the accompanying drawings. The carrier structure isdescribed in the context of a complete reflector system.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings—

FIG. 1 shows a perspective view of the reflector system with a carrierstructure of the system rotated to an angular position in which areflector element is orientated to reflect in an upward direction,

FIG. 2 shows a perspective view of the same reflector system but withthe carrier structure rotated through approximately 180 degrees toexpose the underside of a platform and skeletal frame structure for thereflector element,

FIG. 3 shows, on an enlarged scale, a portion of an end member and adrive system of the reflector system, and

FIG. 4 shows, also on an enlarged scale, a portion of the end member andan associated mounting arrangement for the reflector system.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

As illustrated, the reflector system in its exemplified embodimentcomprises a carrier structure 10 to which a reflector element 11 ismounted. The carrier structure itself comprises an elongated panel-likeplatform 12 which is supported by a skeletal frame structure 13. Theframe structure includes two hoop-like end members 14.

The members 14 are centred on and extend about an axis of rotation thatis approximately coincident with a central, longitudinally-extendingaxis of the reflector element 11. The axis of rotation does not need tobe exactly coincident with the longitudinal axis of the reflectorelement but the two axes desirably are at least adjacent on another.

In terms of overall dimensions of the reflector system, the platform 12is approximately twelve meters long and the end members 14 areapproximately two meters in diameter.

The platform 12 comprises a corrugated metal panel and the reflectorelement 11 is supported upon the crests of the corrugations. Thecorrugations extend parallel to the direction of the longitudinal axisof the reflector element 11, and the platform 12 is carried by sixtransverse frame members 15 of the skeletal frame structure 13. End onesof the transverse frame members 15 effectively comprise diametralmembers of the hoop-like end members 14.

The transverse frame members 15 comprise rectangular hollow sectionsteel members and each of them is formed with a curve so that, when theplatform 12 is secured to the frame members 15, the platform is causedto curve concavely (as viewed from above in FIG. 1) in a directionorthogonal to the longitudinal axis of the reflector element 11. Thesame curvature is imparted to the reflector element 11 when it issecured to the platform 12.

The radius of curvature of the transverse frame members 15 is in therange of twenty to fifty meters and preferably of the order ofthirty-eight meters.

The skeletal frame 13 of the carrier structure 10 also comprises arectangular hollow section steel spine member 16 which interconnects theend members 14, and a space frame which is fabricated from tubular steelstruts 17 connects opposite end regions of each of the transverse framemembers 15 to the spine member 16. This skeletal frame arrangement,together with the corrugated structure of the platform 12 provides thecomposite carrier structure 11 with a high degree of torsionalstiffness.

The hoop-like end members 14 are formed from channel section steel, suchthat each end member is provided with a U-shaped circumferential portionand, as shown in FIG. 4, each of the members 14 is supported forrotation on a mounting arrangement that comprises two spaced-apartrollers 18. The rollers 18 are positioned to track within the channelsection of the respective end members 14, and the rollers 18 provide forturning (ie, rotation) of the carrier structure 10 about the axis ofrotation that is approximately coincident with the longitudinal axis ofthe reflector element 11.

As also shown in FIG. 4, a hold-down roller 18 a is located adjacent thesupport rollers 18 and is positioned within the associated end member 14to prevent lifting of the reflector system under adverse weatherconditions.

A drive system, as shown in see FIG. 3, is provided for impartingunidirectional drive to the carrier structure 10 and, hence, to thereflector element 11. The drive system comprises a shaded pole or othersimilar such non-reversible electric motor 19 having an output shaftcoupled to a sprocket 20 by way of reduction gearing 21. The sprocket 20meshes with a link chain 22 through which drive is directed to thecarrier structure 10.

The link chain 22 extends around and is fixed to the periphery of theouter wall 23 of the channel-section of one of the end members 14. Thatis, the link chain 22 affixed to the end member effectively forms a typeof gear wheel with which the sprocket 20 engages.

With the end member 14 having a diameter in the order of 2.00 m and thesprocket 20 having a pitch circle diameter of 0.05 m, reduction gearingand torque amplification in the order of (40.r):1 may be obtained, wherer is the reduction obtained through gearing at the output of theelectric motor 19.

The reflector element 11 is formed by butting together five glassmirrors, each of which has the dimensions 1.8 m×2.4 m. A siliconesealant is employed to seal gaps around and between the mirrors and tominimise the possibility for atmospheric damage to the rear silveredfaces of the mirrors, and the mirrors are secured to the crests of theplatform 12 by a urethane adhesive.

The mirrors have a thickness of 0.003 m and, thus, they may readily becurved in situ to match the curvature of the supporting platform 12.

Depending upon requirements, two or more of the above describedreflector systems may be positioned linearly in a row and be connectedone to another by way of adjacent ones of the hoop-like end members 14.In such an arrangement a single drive system may be employed forimparting unidirectional drive to the complete row of reflector systems.

Variations and modifications may be made in respect of the carrierstructure as above described by way of example without departing fromthe scope of the appended claims.

1. A carrier structure for a reflector element, for use in a solarenergy reflector system, and which comprises: a reflector element; aplatform which is separate from the reflector element and upon which thereflector element is mounted, and which is formed with stiffeningelements; a frame structure supporting the platform, wherein the framestructure comprises a space frame; at least one curved transverse framemember; and a mounting arrangement supporting the frame structure in amanner that accommodates turning of the carrier structure about an axisof rotation that lies substantially coincident with a longitudinal axisof the reflector element when mounted to the platform, wherein the spaceframe comprises struts connecting opposite end regions of the at leastone curved transverse frame member to a spine member; wherein theplatform is secured to the at least one curved transverse frame memberin a manner such that the curvature of the at least one curvedtransverse frame member causes the platform to curve concavely, andwherein the reflector element is secured to the platform in a mannersuch that the curvature of the platform causes the reflector element tocurve concavely.
 2. The carrier structure as claimed in claim 1 whereinthe platform comprises a corrugated metal panel, with the corrugationsforming the stiffening elements, and wherein the reflector element issupported upon the crests of the corrugations.
 3. The carrier structureas claimed in claim 2 wherein the stiffening elements are orientated toextend in a direction parallel to the axis of rotation.
 4. The carrierstructure as claimed in claim 1 wherein the platform comprises apanel-like platform, wherein the stiffening elements are formed asflutes in the platform and wherein the reflector element is supportedupon crests of the flutes.
 5. The carrier structure as claimed in claim1 wherein the platform is curved concavely in a direction orthogonal tothe axis of rotation.
 6. The carrier structure as claimed in claim 5wherein the platform is curved with a radius of curvature within therange of 20 to 50 meters.
 7. The carrier structure as claimed in claim 1wherein the reflector element comprises a panel-shaped glass mirror. 8.The carrier structure as claimed in claim 1 wherein the reflectorelement comprises a plurality of edge-abutting glass mirrors.
 9. Thecarrier structure as claimed in claim 1 wherein the reflector element isadhered to the platform.
 10. The carrier structure as claimed in claim 1wherein the frame structure comprises hoop-like end members that extendabout the axis of rotation of the carrier structure and wherein theplatform extends in the longitudinal direction between the end members.11. The carrier structure as claimed in claim 10 wherein the end membersare supported for turning upon the mounting arrangement.
 12. The carrierstructure as claimed in claim 10 wherein each said hoop-like end memberhas a channel-section circumferential portion and a diametricallyextending member that is constituted by one of the curved transverseframe members.
 13. The carrier structure as claimed in claim 12 whereinthe mounting arrangement comprises spaced-apart supporting rollers whichtrack within the circumferential portion of associated ones of the endmembers.
 14. The carrier structure as claimed in claim 13 wherein thedrive system comprises: a) a link chain that extends around and is fixedto the end member to form a gear wheel; b) an electric motor; and c) asprocket for transferring drive from the motor to the link chain. 15.The carrier structure as claimed in claim 10 and further comprising adrive system for imparting unidirectional turning drive to the carrierstructure by way of at least one of the end members.
 16. The carrierstructure as claimed in claim 10, wherein each of the hoop-like endmembers has a diametrically extending member that is constituted by oneof the curved transverse frame members, and wherein the space frameconnects opposite end regions of each of the curved transverse framemembers to a spine member.
 17. The carrier structure as claimed in claim16, wherein the spine member interconnects the end members.
 18. Thecarrier structure as claimed in claim 10, wherein the mountingarrangement further comprises a hold-down roller which prevents thelifting of the end members.
 19. The carrier structure as claimed inclaim 10, wherein two or more carrier structures are positioned linearlyin a row and are connected to one to another by way of adjacent ones ofthe hoop-like end members.
 20. The carrier structure as claimed in claim19 and further comprising a drive system for imparting unidirectionalturning drive to the row of two of more carrier structures by way of atleast one of the end members.
 21. A carrier structure for a reflectorelement, for use in a solar energy reflector system, and whichcomprises: a platform which is separate from and is arranged to carrythe reflector element and which is formed with stiffening elements, aframe structure supporting the platform, wherein the frame structurecomprises a space frame, and wherein the frame structure compriseshoop-like end members that extend about the axis of rotation of thecarrier structure and wherein the platform extends in the longitudinaldirection between the end members, wherein each of the hoop-like endmembers has a channel-section circumferential portion, wherein thecarrier structure comprises at least one curved transverse frame member,wherein the space frame comprises struts connecting opposite end regionsof the at least one curved transverse frame member to a spine member,wherein the platform is secured to the at least one curved transverseframe member in a manner such that the curvature of the at least onecurved transverse frame member causes the platform to curve concavely,and wherein the reflector element is secured to the platform in a mannersuch that the curvature of the platform causes the reflector element tocurve concavely; and a mounting arrangement supporting the framestructure in a manner that accommodates turning of the carrier structureabout an axis of rotation that lies substantially coincident with alongitudinal axis of the reflector element when mounted to the platform,wherein the end members are supported for turning upon the mountingarrangement, and wherein the mounting arrangement comprises spaced-apartsupporting rollers which track within the circumferential portion ofassociated ones of the end members.